The purpose of this study was to investigate the personality traits in constitutional types. The Questionnaire for the Sasang Constitution Classification Ⅱ and Eysenck Personality Questionnaire were completed by 155 university students. Statistical analyses of the Questionnaire for the Sasang Constitution Classification Ⅱ and Eysenck Personality Questionnaire scale scores and results are as follows : First, Personality differences in constitutional types are revealed significantly with respect to Eysenck Personality Questionnaire scales such as neuroticism, addiction, and criminality. Second, there is a significant difference between Eum(음) type and Yang(양) type along psychoticism and neuroticism. Third, sex difference is significant along the dimension of extraverion-intraversion.